Auto body repair & detailing: autobody painting., purple paint, mustang lx

Question
Hey Brian
I have a 1988 mustang lx 5.0 H.O. I have recently carved a mural of flames turning into a horse head and front legs, on my drivers side door, into the existing paint of purple, I now want to put in the background colour of black, but everytime I mask the purple, and paint on the black, the tape pulls of the purple paint. I have redone the purple about 3 times now, using different masking tapes, the last one was a professional brand desighned not to remove paint and it did. I even clear coated the mural and left it alone for 2 years. This year I went to finish it and it still peeled off. This is very frustrating, and was about to just paint it all black,( you can still see the mural if you look, cause it is 3-D!) when I found you on this site.
I hope you can give me some advise on how to blend the mural without tape, or using a brush ( boy was that shitty looking) I am currently using Duplicolor Paint, primer and sealant.
Thanks for your time,
char

Answer
The problem you are having is poor adheshion of your purple paint. Sand the purple off is an option. Or borrow someones airbrush and paint your black on in a very tight line and you can fade the black into the purple'



                           Hope this helps
                                Brian